Summary: I've turned Time Machine off. I don't want to use it. However, when I plug in a new disk, Time Machine asks to use the disk for Time Machine backups. It shouldn't keep asking me after I've turned it off. Steps to Reproduce: 1. Open System Preferences. 2. Select Time Machine pane. 3. Turn Time Machine Off. 4. Close System Preferences. 5. Plug in a new external hard drive. Expected Results: Time Machine should not ask. It shouldn't do anything, it's off. Actual Results: Time Machine asks to use the external hard drive for backups. Regression: This also occurs with an old disk if I reformat or repartition it, so that the disk looks new to Time Machine. It happens on two difference machines, a 2.33GHz Intel Core 2 Duo MacBook Pro and a 1.83GHz Intel Core Duo iMac, both running OS X 10.5.5. Note: This bug is undoubtedly a duplicate. 21-Jan-2009: Engineering has determined that this issue behaves as intended based on the following information: To make it stop asking, have it pick a random disk, then turn the backup switch to OFF. TM will stop asking to configure itself on disk insertion and will not attempt to backup either. 21-Jan-2009 Jeff Johnson: What you offered is a workaround for the bug. That doesn't mean it isn't a bug. Why would any user expect that's the way it's supposed to work? I certainly didn't expect that. I don't understand how you can think that it behaves correctly. 10-Jul-2009: Engineering has determined that this issue behaves as intended.